The invention relates to a device for attaching a backrest of a vehicle seat.
As shown in FIG. 1, the known backrests of a rear seat (not illustrated) of a motor vehicle are attached in the region of the wheel housings 2, exterior to the vehicle, via backrest support panels 1, and via a center bearing 3 on the rear structure of a motor vehicle, collectively designated as reference numeral 4. The force acting on a vehicle occupant in a rear-end collision is transmitted to the rear structure via the backrest. As shown in greater detail in FIG. 8, this causes a relatively severe deformation of the backrest support panels 1 and the center bearing 3, resulting in a great change in the angle α of the backrest 5 of approximately 30°. This subjects the vehicle occupants 6 to relatively high stress due to the displacement in the upper body area and in particular the head area.
The object of the invention is to design the device for attaching the backrest of a motor vehicle seat in such a way that stress on a vehicle occupant is reduced in the event of a rear-end collision.
This object is achieved by use of a device having the features of claim 1.
The core concept of the invention is to attach the backrest of a motor vehicle seat via a crossmember on the rear structure of the motor vehicle in such a way that in a rear-end collision the acting forces are largely dissipated in the crossmember. It is essential to the invention that the crossmember which dissipates energy is connected between the body of the motor vehicle and the support for the backrest in such a way that a significant portion of the collision energy may be dissipated. In a rear-end collision this reduces the angle by which the backrest is displaced opposite the direction of travel. In particular for compact vehicles, this prevents the head of a rear passenger from coming into contact with a rear window frame located behind the rear seat assembly.
A crossmember which extends transversely over the width of the vehicle for supporting a motor vehicle seat is known from DE 100 54 586 A1. In contrast to the present invention, however, the known crossmember supports seat rails for attaching the entire rear seat assembly. The known system does not provide an attachment solely of the backrest with an advantageous design for beneficial energy absorption in a rear-end collision.
According to one advantageous embodiment of the invention, front and rear boundary walls of the crossmember extend substantially in parallel in approximately vertical transverse planes of the vehicle. As a result of this design of the crossmember, in a rear-end collision the crossmember is deformed in the manner of a parallelogram essentially over its entire extension in the direction transverse to the vehicle, resulting in correspondingly high dissipation of energy in the crossmember. This reduces the proportion of the collision energy which must be dissipated by the supports for the backrest, resulting in less deformation of the supports and thus a smaller change in the angle of the backrest. The extent of the change in the angle of the backrest is also reduced by the fact that in a vehicular collision, as a result of the parallelogram-like deformation the crossmember is displaced primarily in the longitudinal direction of the vehicle. Only limited twisting of the crossmember occurs.
The supports for the backrest, which are designed as bearing blocks, are preferably provided in the form of swivel bearings to allow the backrests of the rear seat assembly to be folded down, thus increasing the storage space in the trunk in the region of the rear seat assembly. For a two-part backrest of a rear seat it is particularly advantageous to provide in addition to the two exterior swivel bearings a center bearing which takes over the support of the two backrest sections.
Even though the invention is described primarily in conjunction with backrests of rear seats, in principle the device may also be used on front seats of motor vehicles.
Advantageous embodiments of the invention are the subject matter of the subclaims.
One possible exemplary embodiment of the invention is illustrated in the drawings and described in greater detail below. The drawings show the following: